<mark></mark> element was introduced in HTML5 and Gecko 2. It represents highlighted text (a bunch of text marked for reference purpose, due to its relevance in another context). For example it can be used in a page showing search results to highlight every instance of the searched keyword. When used in a quotation or other block of text referred to from the prose, it indicates a highlight that was not originally present but which has been added to bring the reader's attention to a part of the text that might not have been considered important by the original author when the block was originally written, but which is now under previously unexpected scrutiny. When used in the main prose of a document, it indicates a part of the document that has been highlighted due to its likely relevance to the user's current activity.
<p lang="en-US">Consider the following quote:</p> <blockquote lang="en-GB"> <p>Look around and you will find, no-one's really <mark>colour</mark> blind.</p> </blockquote> <p lang="en-US">As we can tell from the <em>spelling</em> of the word, the person writing this quote is clearly not American.</p>